Enhanced stability of Al7H3 and Al7H7 clusters

Based on density functional theory, geometric and electronic properties of Al7Hn (n = 1–3 and 7) clusters are studied. Hydrogen atoms prefer to the top site of Al atoms and do not significantly change the geometry of Al7. A large HOMO–LUMO gap, low-electron affinity, and high ionization potential being the characters of a magic cluster are found for Al7H3. Surprisingly, Al7H7 is found to may have special stability due to its gap is even larger than that of Al7H, which was known as a magic cluster. Mulliken population analysis and energy spectrum are used to discuss the bonding nature.